The present invention relates to a sputtering method and sputtering apparatus for the sputtering method.
Here the sputtering is explained in a semiconductor device fabrication process. In forming electrodes and patterns on objects to be processed, such as semiconductor wafers, forming insulating films, etc. for device isolation, conventionally the objects to be processed, required electrodes, and targets of pattern materials and insulation materials are opposed to each other in a processing chamber with a required low pressure atmosphere being established therein, and deposition particles (deposition seeds) sputtered from the targets by glow discharges, etc. are deposited on the objects to be processed.
Recently as semiconductor devices are integrated higher, semiconductor device fabrication processes are required to have techniques for more micronized processing with high precision. For example, processing for internal wiring of a device requires to fill grooves of a high aspect ratio which have small openings and a large depth, with a required wiring deposition seed or insulation deposition seed.
In the conventional sputtering method and system, in such case, deposition seeds sputtered from a target by glow discharges or others do not have a uniform sputtering direction. That is, ratios of vertical components and horizontal components of the sputtered particles are various. In depositing the deposition seeds first on the bottoms of grooves or holes of a high aspect ratio formed in the surfaces of the objects to be processed, more of the deposition seeds are adversely deposited on the peripheral parts of the grooves and holes. As a result, voids occur in the bottoms of the grooves and holes and inside the grooves and holes, which may cause wiring breakage and defective insulation.
To prevent such occurrence, it is preferred to constrain the deposition seeds sputtered toward the objects to be processed to cause them to vertically enter the grooves and holes, decreasing horizontal the component of the deposition seeds, to be deposited there. To this end has been proposed a method by which the deposition seeds sputtered from the target are constrained by a collimator having, e.g., a plurality of vertical circular through-holes or vertical honeycomb-shaped through-holes disposed between the target and the objects to be processed so as to vertically enter the objects to be processed. This method, however, decreases number of the deposition seeds which enter the collimator, with results that deposition rates are lowered, and deposits take place on the collimator itself due to clogging, and the deposits may peel into particles and contaminate the interior of the processing chamber.